1. Field of the Invention
The present invention relates to a machine tool including a spindle supporting mechanism movably supporting a spindle disposed on a bed, and more particularly, to improvement in a supporting structure of a ram supporting the spindle.
2. Description of the Related Art
An example of a machine tool of this type is structured such that a saddle is supported by a column disposed on a bed to be movable in an up/down direction, and a ram (spindle head) is supported by the saddle to be movable in a front/back direction. In this machine tool, the ram is movably supported by a pair of left and right guide rails disposed on a flat surface extending in the front/back direction of the saddle (see, for example Patent document 1).
[Patent document 1] Japanese Patent Application Laid-open No. 2000-24853
Incidentally, if the structure in which the ram is supported by the left and right guide rails disposed on the flat surface as in the above-described conventional machine is adopted, it may possibly become difficult to ensure positioning accuracy of the ram in a left/right direction perpendicular to the left and right guide rails, which gives rise to a concern about the influence to machining accuracy.